Gut-off-valve gear



(No Model.) v

G. M. CONWAY.

GUT-OPF VALVE GEAR. @269,265 .Patented Dec. 119 1882.

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N. FErERS, Photnuthqmpher, wanu'ngum D. C.

'PATENT FFICE GEORGE M. CONWTAY, OF MILWAUKEE, VISCONSIN.

CUT-OFF-VALVE GEAR.

SPECIFICATION forming part of Letters Patent No. 269,265, dated December19, 1882.

Application filed December 13, [881. (No model.) y

To all Iwhom it muy concer/n Be it known that I, GEORGE M. CONWAY, ofMilwaukee, in the county ot' Milwaukee,and in the State ot' isconsin,have invented certain new and useful Improvements in AutomaticGut-OftValve Gear for Steam-Engines; and I do hereby declare that thefollowing is a full, clear, and exact description thereof.

My invention relates to automatic-cut-oi steamengines, and will be fullydescribed hereinafter.

In the drawings, Figure lis a side view of my improved engine. Fig. 2 isa detail. Fig. 3 is a top view, and Figs. 4 and 5 are details.

A is the steam-chest, and B B are two valvechambers con taining each agrid'iron-valve, a.

b b are the valve-rods, each of which has an enlargement, b, that servesas a piston.

After passing through the bottom ofthe valvechest the rods b b',extending nearly to the bed-frame of the engine, are provided there withair-caps g, that nt upon stationary heads g'. This part of my inventionwill be morev fully described farther on. The upper end of the rod bisprovided with a trip-ferrule, o, and the rod b with a similar one, c. Inferrule c is pivoted a trip, d, and in ferrule c a trip, d. The trips (land Fare precisely alike, and a description of one will answer for both,and therefore I will referto trip d. (Shown in detail to the left ofFig. 1.) 'Ihe trip d consists ot' an upright portion recessed in frontto receive a hard-metal plate, e, and beneath it a cushiomf The plate eprojects beyond the cushion j' to receive a plate, m, on the top,andcushion f receives the end of beam H. On the lower end ofthe trip d is arounded shoulder, It, through which the boltl by which it is pivoted tothe ferrule c passes, and this bolt is directly on a line with the platec.

Projecting` from trip d, and just back of shoulder IL, is an arm, t',and a spring,j, secured to ferrule c, bears upon the under side of arm ito throw the trip forward against the end of beam H. A post, D,justbehind trip d, carries another trip, M, that has an arm, N, projectingover arm i oftrip d, and trip M is connected to one end of a lever, F,on rock-shaft j G by a rod, E, and the other end of this lever isconnected by a rod, E', to a trip, M. The rock-shaft F is bracketed tothe governorstand G, and its arm P is pivoted to the slide ofthegovernor-stem,- (not showm) so that when the slide is raised by the armsofthe governor as they are thrown out by an increase in the velocity oftheir revolution the arm I? ofthe rock-shaft will be drawn up, causinglever F to pull rod E and thrust rod E. rIhe beam H is trunnioned to thesteam-chest midway between posts D and D', and, when horizontal,projects on each side suliiciently far to touch each of the cushions fof the trips d and d when said trips are in a vertical position, as

shown. Fig. l ofthe drawings shows the po,

sition of the parts of my engine when the eef centric ou thedriving-shaft (not shown) is at haltltravel. Both valves are barelyclosed, and their rods are suspended each from one end of the beam H.Now, as the eccentric continues on toward the completion of its travelits rod K', thrusting upon the arm Kof beam H, will cause it to dip oneend, m', and elevate the other, m, and the latter will carry the trip dup with it until its arm t' strikes the arm N of trip M and trips it outot' engagement with the beam. Instantly upon the trip d being releasedby the beam H its rod b will be drawn down'by steam-pressure on thepiston b" of rod b to close the valve a. The other end ot' beam acts inprecisely the same Way upon trip d and valve-rod b.

It will be seen that the lever F is exactly vertical. rIhis is itsposition when the engine is at its normal speed and the trips M Mare inposition to limit theperiod between the pulsations of the valves to justthe work needed; but should the supply of steam decrease, or shouldadditional machinery be belted to the engine, then just-as soon as thedriving-shaft begins to slow up the balls ot' the governor, falling,will throw the lever F out ofa perpendicular and cause its rods to tiltthe trips M. M away from trips d d', so as to permit the rods b b to becarried higher by the beam before the tripping takes place. Vhen thee11- aine is at rest the governor-arms hang down toward a verticalposition, and the rods E E hold the' arms M M entirely out of the way oftrips (l d', so that when the ends of beam H rise and fall they carrythe trips with it both ways, alternately opening and closing the valvesaand holding each open as long as the driving-piston is going from it,and this col1- tinues until the governor-arms leave the stand IDO andbegin to draw upon the arm' of rock-shaft IP. This immediately throwsthe lever F into a perpendicular and causes its rods-E E' to throw thetrips M M into position to throw trips d d out of contact with beam Hand shorten the stroke of valve-rods b b snfticien tl yA to cut 0E steamso rapidly that only sufficient will be permitted to enter the cylinderat each pulsation to propel the piston from one end to the other andkeep up its motion, and thus any increase or decrease in the speed ofthe governor be corrected by cutting off steam earlier or later in thestroke of the engine, according to the requirements of the work to bedone by the eng-ine, keeping the speed always uniform. In fact I have byactual' test found tha-t the variation in the motion of my engine is notmore than half of one per cent. between the two extremes of running thefriction 'of the engine and of carryingher full load, or between thelowest pressure at which steam can be cut oli and keep up the motion andrunning up to one hundred pounds pressure-a result never beforeattained, to my knowledge, previous to this my invention.

To guard against the mischief that might result from the breaking of thebelt or gearing that communicates motion from the drivingshaft to thegovernor-stem, I attach a sprocketwheel, s,to each oft-rips M and M andanother to each of trips d d', and these I connect by a chain. Thesewheels slide upon their pivots, and are locked by pins or any othersuitable means. Afterthe engine has attained her regular speed and thetrips are in the position in Fig. 1, I turn the wheels and tighten thechain. It will now be utterly impossible for the engine to run away,even it' the governor-stem should become disconnected from thedrivingpower and the governor-arms, should fall, for their falling,instead of relieving the trips d d', will cause the trips M M to drawthem entirely out of contact with the beam H, so that its oscillationswill not raise the valve-rods to admit steam to the cylinder. Of coursethe chain must have slack enough to permit the regular action of thetrips when the governor-armsare revolving.

Each air-cushion consists of a cap, g, secured to the lower end of itsvalve-rod, and having an annular depression, h', in its top, and grooveso in its lower portion or rim. This cap tits over a stationary head, g',that is cast with a central screw-threaded cylinder, h", to receive thescrew-threaded bushing l of a needle-valve, l. On its top the head g hasa circular projection that fits in the depression h', and an aperture,n', serves to permit the escape ot' air to the cylinder h, from whenceit escapes to an annular chamber between the cylinder IL and the wallsof head g. This escape of air is regulated by the needle-valve l'. Isecure a packing-ring about the head g', and below it reduce the headslightly. As the valve-rod is raised it carries the cap g with it, airentering at first through perforations n to prevent the formation of avacuum iu the cap until the cap has raised sufficiently to carry thegrooves o in its sides high enough to open into the space between thecap and the head, and above the packing-ring. On returning the cap meetswith very slight resistance until the grooves o have passed belowthe'packingring. After this occurs the only outlet for the air isthrough perforation n', and by means of the needle-valve l' the size ofthis exit may be regulated to the greatest nicety, so that while theresistance in the cup may not be great enough to prevent the valve cfrom closing it will be a perfect cushion for the rod, and as the airmakes its exit from the cylinder h" into the annulus about the cylinderthe sound produced by the rush of air is deadened.

I l are the rods of exhaust-valves S S', and are connected by a bar, u,with each other and the arm K, so that a forward stroke of arm K, thatwill close exhaust-valve S and open valve S', will cause the beam H toopen valve a, and a backward stroke of arm K, that will open' valve Sand close S', will at the same time close valve a and lit't rod b toopen its valve.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The beam H, pivoted between the upper ends of the valve rods, incombination with tripsone on each valve-rod--adapted each to engage withone end of the beam, and other trips connected with the governor-stemand engaging with the first-named trips, as set forth.

2. The combination of trips d d and M M',

connected by chains or cords, and a windingv device, with rods E E',connecting them with the governor-stem, as set forth.

3. The valve-rods having enlargements b i for receiving thereturningimpact ofthe steam,

and having caps g on theirlower ends, in combination with stationaryheads, each head having a central cylinder, h2, apertured to permit theescape of air through it from between the cap and head into an annulusaboutit, (the said cylinder,) as set forth.

4. Cap g, the wall of which is grooved on IOO IOS'.

IIO

its inside vertically, in combination with the head having its wallreduced on its outside, and having a packing-ring about it just aboveits reduced portion, as set forth.

5. The cap g. in combination with head g', having a central cylinder, h,with apertures leading from between the head and its cap into an annularchamber between the cylinder and the outer wall ot' the head fordeadening the sound occasioned by the expulsion of the air, as setforth.

In testimony that Iclaim the foregoing I have hereunto set my hand this7th day of Novcmber, 1881.

GEO. M. CON WAY.

Witnesses:

STANLEY S. S'roU'r, HAROLD G. UNDERwooD.

